Use of dyes to investigate migration of the chiral selector in CFFE and the impact on the chiral separations

Continuous free flow electrophoresis was investigated as a tool for the pre parative chiral separation of piperoxan enantiomers using sulfated beta -cy clodextrin (s beta -CD) as the chiral additive. Bulk migration of s beta -C D was confirmed using LC-MS analysis of the individual fractions collected and visualized with the addition of crystal violet to the separation buffer . In the absence of s beta -CD, the crystal violet-containing buffer was re ddish/purple and the crystal violet was deflected cathodically in the chamb er. In the presence of s beta -CD, the crystal violet-containing buffer was blue and was deflected anodically. However, formation of accumulation and depletion zones was apparent in both cases. The addition of s beta -CD to t he cathodic wash solution allowed for almost complete resolution of the pip eroxan enantiomers with a processing rate of 0.45 mg/h.